Method of manufacturing circular laminated printing plates



H. H. HORST May 6, 1958 METHOD CR MANUFACTURING CIRCULAR LAMINATRDPRINTING PLATES Filed OCT.. 8. 1956 ooooooooo ooooooooo o oooo oooo,

United States Patent METHOD F MANUFACTURING CIRCULR LAMINATED PRINTINGPLATES This invention relates to the printing art and more particularlyto improvements in the eld of lamination employed in the manufacture ofcurved printing plates used extensively in magazine and newspaperprinting, as well as in telephone and-catalogue work employing a curvedplate. This type of press may be a rotary press, a multi-color press, orpresses known in the art by several other names, but all such pressesemploy an arcular, or what is well known to the trade as a curvedprinting plate, and it is in the manufacture of the latter to which theinstant invention is particularly directed.

As now carried out such manufacture is very costly and requires manyoperations involving labor and material and in time consumed. It istherefore a very important feature of my invention to provide a simplemethod of lamination that includes improved means of fortifying andlaminating simultaneously, resulting in less plate distortion withminimum shrinkage, and greatly improved control for accurate multi-colorregistry.

A further object is to provide a better curved plate for chromingoperations which is also a lighter plate that is more easily handled andone that will stand up well through long use and long press runs. It iswell known that there exists a constant demand for higher printingspeeds and for plates that have strong resistance to crackmg andbreakage as such occurrences cause unlimited damage to equipment,astronomical spoilages and hazardous working conditions for the presscrews.

The printing trade has 'been and is demanding more and -better platesfaster, resulting in the introduction recently of what is known as thecentrifugal casting mat chine. In this machine individual electroplatedshells, joined by a strip clincher, are placed and the casting drumrotated. Backing metal is then poured, by means of a ladle, and thecentrifugal force caused by the rotating drum effects a comparativelyuniform cast. It is in the operation of this machine that the instantinvention is employed to realize my improved technique. There are othercasting machines, stereotype and electrotype that might readily beadapted to the lamination principle, the

centrifugal caster being merely an object of demonstration.

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Fig. 6 is an enlarged fragmentary view of thev screen and matrix shellinthe drum prior to casting, and,

Fig. 7 is a vertical sectional view of a typical casting drum adaptedfor casting. Y v

The reference numeral 19 denotes a handle having an extension 11 forsupplying the molten or backing metal by means of a ladle 12. Mounted toor supported in a centrifugal caster is the casting drum 13 which isspun by conventional spinning rollers 14, 15, 16.

The first step in the operation is the preparation of a plated shell 17,or shells, joined together by a strip clincher 17a, which shell orshells, is placed within the casting drum and the drum is rotated after,however, a precurved aluminum fortifying member 18 is also placed orinserted inside the shell 17. This member 18 may be a one piece circularmember or it may be formed of sections, one section of 120 degrees andone section of 240 degrees; or it may be composed of three identicalsec- With the foregoing and other objects inview my invention consistsin the method whereby the foregoing and other objects are realized asset forth in the following specification, defined in the claims andillustrated in the accompanying drawing forming part of this disclosureand wherein:

Fig. l is an edge View of a reinforcingrscreen employed.

Fig. 2 is a longitudinal view of Fig. 4, with parts broken away andsectioned. Y

Fig. 3 is an enlarged fragmentary sectional view of the screen withinthe connes of the nished plate, ready for printing.

Fig. 4 is a detail cross sectional view of. the printing plate or drumtakenon the line 4-4 of Fig. 2.

Fig. 5 is a sectional view of the casting drum with screen and matrixshell in place for backing.

tions of degrees each. These members are formed desirably of aluminumsheet, cut to size, with a plurality of holes 19 drilled or punchedtherethrough, thus forming a screen through which the backing metal ispoured while the casting drum is rotated.

It will be readily understood that, due to the casting drum rotation,the joined electroplated shells 17 and the fortifying aluminum screenmember, or members 18, are pressed together -by centrifugal force,suiciently spaced however, to provide perfect sandwiching of the member18 in the finished product, Fig. 4, and are fitted most intimatelyagainst the inner periphery of the casting drum.

While the backing metal is being poured the metal is perfectly screenedby passing through the holes of the fortifying member 18, eliminatingall air bubbles and distributing the backing material uniformly over theentire cast. Sucient metal is poured so that after the finished platesare shaved to the proper thickness the fortifying lamination member isspaced properly within the connes of the plate. This fortifying membermay be of any desired thickness depending upon the thickness of thefinished plate in which it is to be used. The ends of the drum 13 arepartially closed by a pair of identical removable rings 20, to keep theassembly aligned after it has been placed within the drum, these ringsbeing removed before withdrawal of the cast.

While I prefer the use of aluminum or an alloy, it is possible to employany non-ferrous metal. When the electroplated shells 17 are cooled andremoved from the drum they are placed in the press for printing.

t What is claimed is:

1. The method of manufacturing curved laminated printing plates whichconsists in the placement of a curved electroplated shell bearingprinting indicia in the casting drum of a centrifugal caster, placing acomplementarily formed perforate fortifying member within said shell,rotating said drum, providing a continuous iiow of fused backingmaterial to said fortifying member to pass through the perforateportions thereof and over the outer face of said fortifying member andover the adjacent back ofY said shell while said casting drum is beingrotated, and removing, cooling and shaving the plate tothe desiredthickness for placing said plate on a printing press.

2. The method of manufacturing curved laminated printing plates whichconsists in the placement of a curved electroplated shell bearingprinting indicia in the casting drum of a centrifugal caster, placing acomplementarily formed perforate fortifying member within said shell,rotating said drum, providing a continuous flow of fused backingmaterial to said fortifying member in said drum as same is rotating tocause said material to pass through said fortifying member perforationsand over the adjacent back of said shell thus fortifying and laminatingthe plate simultaneously, and removing, cooling and shavrammedMay s, sy

F ing the plate to the desired thickness for placing same on the press.

3. The method of manufacturing sectional circular laminated printingplates which consists in the placement of a sectional electroplatedshell bearing lprinting ,indicia in the circular casting drum of acentrifugal caster, connecting said plate sections by strip clinchers,placing a complementarily formed perforate tortifying member within saidshell, rotating said drum, providing a continuous flow of fused backingmaterial to said fortifying member as said drum is rotating to causesaid material to pass through said fortifying member perforations andupon the back of said shell, and removing, cooling and "X shaving theplate to the desired thickness for placing same on the press.

References Cited in the file of this patent UNITED STATES PATENTS1,028,330 Cooper June 4, 1912 1,718,210 Armstrong June 25, 19292,162,825 Richards June 20, 1939 2,305,852 Durham Dec. 2,2, 19422,670,326 Bungay Feb. 23, 1954 2,685,129 Meyers Aug. 3, 1954

